/*
 * Copyright (C) 2017 zhouyou(478319399@qq.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dankegongyu.lib.http.func;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Modifier;

import io.reactivex.annotations.NonNull;
import io.reactivex.functions.Function;


/**
 * 请求结果转换
 */
public class ApiFunction<R> implements Function<String, R> {

    private Gson gson;
    private Class<R> clazz;
    private TypeToken<R> typeToken;

    public ApiFunction(Class<R> clazz) {
        init();
        this.clazz = clazz;
    }

    public ApiFunction(TypeToken<R> typeToken) {
        init();
        this.typeToken = typeToken;
    }

    private void init() {
        gson = new GsonBuilder()
                .excludeFieldsWithModifiers(Modifier.FINAL, Modifier.STATIC, Modifier.TRANSIENT)
                .create();
    }

    @Override
    public R apply(@NonNull String string) throws Exception {
        if (clazz != null) {
            return gson.fromJson(string, clazz);
        } else if (typeToken != null) {
            return gson.fromJson(string, typeToken.getType());
        }
        return null;
    }

}
